The kinetic model of the co‐polycondensation with A2 and AB2 type monomers is developed and the analytical expressions of the various molecular parameters of the products are derived rigorously. The monomer feed ratio (α) of A2 to AB2 significantly affects the molecular parameters and the critical condition of gelation. Gelation can be avoided if α is > . At the critical state, the degree of branching decreases firstly and reaches its minimum value at about α≈0.22. Then, it increases with increasing α‐value. In comparison with experimental results, non‐equal reactivity of the active groups should be considered.
. At the critical state, the degree of branching decreases firstly and reaches its minimum value at about α≈0.22. Then, it increases with increasing α‐value. In comparison with experimental results, non‐equal reactivity of the active groups should be considered. 